Evaluating the impact of treatment timing with recombinant human thrombopoietin for cancer treatment–induced thrombocytopenia: A retrospective cohort study.

12127 Background: Recombinant human thrombopoietin (rhTPO) is utilized for cancer treatment-induced thrombocytopenia (CTIT) to ensure timely and full-dose chemotherapy delivery. This study investigated the differential clinical benefits of platelet-guided intervention timing strategies to provide evidence-based support for early initiation protocols. Methods: This single-center retrospective cohort study enrolled CTIT patients receiving rhTPO therapy. Participants were stratified into three groups based on platelet count at rhTPO initiation: early intervention group 1 (platelets 75-<100×10⁹/L), early intervention group 2 (50-<75×10⁹/L), and salvage therapy group (<50×10⁹/L). Comparative analyses among the three groups encompassed time to platelet recovery and recovery rates, severe CTIT incidence, platelet transfusion requirements, bleeding event rates, chemotherapy continuity parameters (dose reduction, delay, or discontinuation), and safety profiles. Results: Among 456 solid tumor patients with CTIT, 159 (34.9%) were in early intervention group 1, 172 (37.7%) in early intervention group 2, and 125 (27.4%) in the salvage therapy group. Median time to platelet threshold achievement was significantly shorter in group 1 (7.0 d) versus group 2 and salvage therapy (both 11.0 d; P <0.001), with concomitantly shorter rhTPO treatment duration (5.0 d vs. 7.0 d vs. 7.0 d; P <0.001). Severe CTIT incidence was significantly reduced in early intervention groups (12.6% in group 1 and 19.2% in group 2 vs. 56.0% in salvage therapy; both P <0.001). Platelet recovery rates were superior in early intervention groups (81.1% in group 1 and 75.0% in group 2 vs. 59.2% in salvage therapy; P <0.001 and P =0.004, respectively). Platelet transfusion requirements were significantly lower (0.6% in group 1 and 1.2% in group 2 vs. 12.0% in salvage therapy; both P <0.001). Chemotherapy continuity was significantly improved, with lower rates of delay/discontinuation (18.9% in group 1 and 33.1% in group 2 vs. 46.4% in salvage therapy; all P <0.05). No significant inter-group differences in bleeding incidence were observed, and no rhTPO-related serious adverse events or thromboembolic events occurred. Conclusions: rhTPO therapy for CTIT exhibits a pronounced threshold effect, with early intervention (platelet count ≥50×10⁹/L) conferring substantially greater clinical benefit than salvage therapy. Initiation at 50-<75×10⁹/L effectively preserves chemotherapy continuity and reduces transfusion burden, while initiation at 75-<100×10⁹/L optimizes platelet recovery kinetics and cost-effectiveness.